As is well known, radioactive materials are used extensively in industrial, medical, agricultural, and environmental activities, among others. For example, radioactive waste is generated in all stages of nuclear reactor operations, and there are a number of liquid processes and waste streams at nuclear facilities that require treatment for removal of radioactive contaminants. Management of this waste typically includes treatment, temporary storage, and transportation of the waste to a permanent disposal site.
A number of processes are available for treating liquid radioactive waste. One such process is known as ion exchange, which is effective for transferring the radioactive content of a large volume of liquid into a small volume of solid. Although ion exchange processes may be implemented in a variety of ways, the most common uses of ion exchange media are as packed beds in vessels. More particularly, an ion exchange medium is typically contained inside a stainless steel pressure vessel, with an engineered inlet, outlet, and flow distribution system to allow liquid to percolate through the bed of the medium at a specified flow rate. Many types of ion exchange media are available for this purpose, including synthetic organic resins.
Over time, however, the ion exchange medium is spent, at which point the vessel is filled with a new medium. The spent ion exchange medium is radioactive waste, and it must either be regenerated or disposed of. During disposal, the spent ion exchange medium can be dewatered or dried and is often transferred from the vessel or an intermediate storage tank to a disposal container. The disposal container, also known as a “high integrity container” (HIC), is typically formed of ductile cast iron, concrete, steel, or high density polyethylene. Alternatively, the ion exchange vessels themselves (containing the spent ion exchange media) can be removed from service and placed in polyethylene HICs for disposal.
In any event, while awaiting transport to a permanent storage/burial site, the HICs are often temporarily stored at the waste processing location. Prior art polyethylene HICs require rounded shoulders at the top and bottom to absorb shocks, and thus a metal basket or nylon straps is required to lift and move the HIC for storage. Additionally, the HICs must be stacked via tables placed between each HIC.
Finally, when the HICs are transported to a final storage/burial site, they may be placed in protective shipping casks, which may be formed of lead or steel.